Java 視窗滑鼠事件實作

在任何視窗程式中，都會有很多關於滑鼠的 Event

譬如：按下或放開滑鼠左鍵、右鍵，或是移入某特定區之類的

以下的程式主要是以一個視窗為底

那當使用者滑鼠移入視窗內時會把始窗的背景色換成黃色

並且在左上方顯示進入視窗的位置

如果在視窗內按下滑鼠左或右鍵　會在點擊處印出　DOWN

放開則會在事件發生處印出 UP

當移出視窗時則會將被景色換成白色

並顯示於哪個位置移出

以上都會實作到很多有關滑鼠的事件

大家可以練習看看，程式如下：

import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class MouseTest extends JFrame
{
   JLabel lbl;
   public static void main(String[] args)
   {
      MouseTest app = new MouseTest();
      app.setSize(300,300);
      app.setVisible(true);
   }
   public MouseTest()
   {
      final Container c = getContentPane();
      c.setBackground(Color.white);
      lbl = new JLabel();  //視窗左上方的 Label
     
      addMouseListener(new MouseAdapter(){
         public void mouseEntered(MouseEvent e){  //當滑鼠游標進入物件範圍
            int x = e.getX();  //擷取發生事件的 X 座標
            int y = e.getY();  //擷取發生事件的 Y 座標
            c.setBackground(Color.yellow);
            lbl.setText("Mouse is moving to" + Integer.toString(x) + "," + Integer.toString(y));
         }
      });
      addMouseListener(new MouseAdapter(){
         public void mouseExited(MouseEvent e){   //當滑鼠游標進入物件範圍
            int x = e.getX();
            int y = e.getY();
            c.setBackground(Color.white);
            lbl.setText("Mouse just left the window from" + Integer.toString(x) + "," + Integer.toString(y));
         }
      });
      addMouseListener(new MouseAdapter(){
         public void mousePressed(MouseEvent e){  //實做滑鼠的點擊事件
            Graphics g = getGraphics();
            int x = e.getX();
            int y = e.getY();
            g.drawString("DOWN",x,y); //在事件發生的座標繪上 "DOWN" 字樣
            lbl.setText("Mouse is pressed at" + Integer.toString(x) + "," + Integer.toString(y));
         }
      });
      addMouseListener(new MouseAdapter(){
         public void mouseReleased(MouseEvent e){  //實做滑鼠的放開事件
            Graphics g = getGraphics();
            int x = e.getX();
            int y = e.getY();
            g.drawString("UP",x,y);
            lbl.setText("Mouse is released from" + Integer.toString(x) + "," + Integer.toString(y));
         }
      });
      addMouseMotionListener(new MouseMotionAdapter(){
         public void mouseDragged(MouseEvent e){  //實做滑鼠的拖曳事件
            Graphics g = getGraphics();
            int x = e.getX();
            int y = e.getY();
            g.drawString("Dragging",x,y);
            lbl.setText("Mouse is Dragging at" + Integer.toString(x) + "," + Integer.toString(y));
         }
      });
      c.add(lbl,BorderLayout.NORTH);
   }
}